Control device for electric motors for rewinding watch movement



y 6 s. SCHWAB 3,319,414

CONTROL DEVICE FOR ELECTRIC MOTORS FOR REWINDING WATCH MOVEMENT Filed Oct. 28, 1965 2 Sheets-Sheet l 87 //1 ///2 f; 9 I. i 7fi Illllll IMIHHHH] IHTIII S. SCHWAB May 16, 1967' CONTROL DEVICE FOR ELECTRIC MOTORS FOR REWINDING WATCH MOVEMENT 2 Sheets-Sheet 2 Filed Oct. 28, 1965 F'IG.4

United States Patent Filed Oct. 28, 1965, Ser. No. 505,525 1 Claim. (CI. 58-41) This invention has for object a control device for an electric motor used for rewinding a watch movement, comprising a stop work mounted rotatingly on the cover of the barrel and actuated by a finger unitary with the shaft of the barrel.

In already known devices of this type where the stop work allows the rewinding of the spring after a certain let down of the spring, corresponding to a predetermined number of barrel turns, a finger unitary with the barrel shaft cooperates with as many radial slots in the stop work; the latter then, mechanically actuates an electrical contact composed of two blades one of which is moved by a member unitary with the stop work while the other is fixed.

Such devices are complicated since, in addition to a mechanical actuating contact member, carried by the stop work, they also require a specific assembly of contact blades on the barrel cover of which at least one must be electrically linked to the motor by an insulated circuit formed of a brush on the barrel sliding on a ring mounted on a bridge.

The device according to the present invention precisely avoids this disadvantage. It is characterised by the fact that the stop work bears a contact surface consisting of two superimposed parts, one of which is conductive and linked to one of the terminals of the motor and the other of which is insulated and by the fact that an insulated elastic conductor is mounted on said cover and bears by one of its extremities, alternately on one and the other of two parts of the contact surface while its other extremity is continuously linked to the other terminal.

The annexed drawing represents by way of example, one embodiment of the present invention.

FIGURE 1 is an elevational view;

FIGURE 2. is a cross-sectional view along line IIII, of FIGURE 1,-

FIGURE 3 shows cross-sectionally a detailed view of FIGURE 1;

FIGURE 4 is a plan view of the details shown in FIG- URE 3.

In this embodiment, barrel I is pivoted between two bridges, of which one only, 2, is shown in the drawing it comprises a drum turning freely around shaft 4 and a cover 5 the motor spring is not shown. A finger 6 is fixably mounted on the shaft of the barrel and engages at each turn of the shaft 4, with respect to drum 3, one of the slots 7 of the stop work 8 rotatably mounted on cover 5.

On the stop work are co-axially secured a conductor sleeve 9, and between a shoulder 10 of the sleeve and the stop work itself, an insulating ring 11 (FIGURE 3).

The sleeve and ring constitute a double annular contact surface 12, of which one part, corresponding to the sleeve, is conductive, while the other part, corresponding to the ring, is insulating. This contact surface 12 forms a truncated cone on the greater part of its circumference and on the other part forms an inclined notch forming with the generatrix of the truncated cone, a 60 angle.

A groove 13 having an axis perpendicular to that of the stop work and parallel to its plane is provided in ring 11 The bottom 14 of the groove lies in the plane of the face of the annular shoulder 15 of the ring.

Mounted on the cover of the barrel is an insulated stud 17 bearing a resilient conductor in the form of a V, one

of its branches 18, hearing against the contact surface 12 while the other branch 19 bears against the conducting ring 20 mounted co-axially with shaft 4 in insulated fashion on bridge 2. The elastic branch 18 bearing against contact surface 12 is urged by its tension when facing the truncated part of this surface, against the shoulder 10 of the conducting sleeve. On the contrary, when owing to the angular displacement of the stop work, branch 18 faces slot 16, it slides on the contact surface and enters into groove 13 in insulated ring 11. The electrical circuit involved comprises the mass of the movement, the barrel, sleeve 9, branches 18 and 19 of the resilient conductor and insulated ring 20. The said circuit is closed when branch 18 bears on the conductive part of the contact surface and is opened when it bears on its insulator part. The mass of the movement can be connected with one terminal of a current source, ring 20 can be connected to one of the poles of the driving motor for the barrel shaft and the other terminal of this motor can be in contact with another pole of the current source.

The spring of the barrel is re-Wound by the rotation of its shaft 4, the stop work, driven in one direction by the finger 6 of the shaft, assumes finally an angular position such that branch 18 engages in groove 13 of the insulating part of the contact surface 11 thus interrupting rewinding. The drum of the barrel activates then the movement and turns until finger 6 has caused the stop work to pivot in the other direction to an angular extent sufiicient that branch 18, escaping from groove 13, slides on the truncated part of the contact surface up to the conductive shoulder of sleeve 9. The electric circuit is again closed and rewinding begins.

The periodic nature of the re-winding is of course arbitrary and corresponds to the number of slots of the stop work as well as to the form of the contact surface, both which may be varied. However, to ensure the best regularity to the movement, it is preferred to maintain the spring under a tension which is as regular as possible and, consequently, to provide a rather frequent re-winding, for example, for each revolution of the barrel.

As various embodiments may be made of the claimed invention, and, as various changes may be made in the embodiment above set forth, it is to be understood that all matter herein set forth or shown in the accompanying drawing is to be interpreted as illustrative, and, not in a limiting sense.

I claim:

A device for electrically controlling the winding up by an electric motor of a spring actuated clockwork comprising a barrel having a cover and a barrel shaft, a stop work rotatably mounted on said cover and having in its periphery a plurality of slots and a finger on said barrel shaft engaging said slots to actuate said stop work, said device comprising:

a conductive sleeve coaxially secured on said stop work and having a shoulder;

an insulating ring coaxially mounted between said shoulder and said stop work, said sleeve and ring forming a double annular truncated contact surface along the major part of the circumference and an inclined notch for a minor portion of said circumference;

a groove in said ring parallel to said stop work and communicating with said notch;

an insulated stud on said cover and a tWo-pronged resilient conductor secured by said stud, one said prong of said conductor being in contact with a terminal of said motor and the other said prong of said conductor being engaged with said shoulder and contact surface of said conductive sleeve to close the motor circuit, rotation of said stop work sleeve and ring caus- 3 4 ing said other prong to slide on said contact surface FOREIGN PATENTS and enter said groove of said insulating part to open Said circuit 394,420 6/1908 Franeel References Cited by the Examiner UNITED STATES PATENTS 1,299,116 4/ 1919 Bryce 58-41 MICHAEL L. LORC-H, GERALD F. BAKER, 2,694,286 11/1954 Frantellizzi 5841 Assistant Examiners.

5 RICHA-RD B. WILKINSON, Primary Examiner. 

